1. Dr. John W. Mabry Iowa Pork Industry Center Iowa State University
Closed Herd Systems: Genetic Systems, Genetic Cost of Production and BLUP Sow Indexing
Dr. John W. Mabry
Iowa Pork Industry Center
Iowa State University
Iowa Pork Industry Center

2. Replacement Rates in Sow Herd
It is a biological certainty that in a swine herd, females will go out of service on a regular basis
due to age, soundness, death, disease, etc
The annual replacement rates of sows has increased dramatically in the past few years
PRRS, more reproductive and fragile genetics
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3. Traditional Production Systems (Genetic Aspect)
Purchase parent stock (PS) females from genetic supplier
Purchase GP females and make PS females within herd
Purchase GGP females and make GP and PS females within herd
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4. Roles of Genetic Supplier and Pig Farm
Genetic supplier provided the genetic progress in the form of healthy animals plus AI
Pig farm simply multiplied the market pigs
Then came PRRS
Many herds now want to be closed to all live animal introductions, will allow AI from PRRS negative studs
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5. Closed Herd Genetic Systems
Maintain purebred GGP females and make GP and PS females using maternal AI lines
Problem in managing purebred females
Problem in managing replacement females through the production system
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6. Iowa Pork Industry Center
GGP Closed Herd
GGP
L x L X X
Grandparent
Y x L X
Parent
Duroc x F1 Y/L
Market Hogs
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7. Closed Herd Genetic Systems
Rototerminal cross system using maternal AI lines
Problem in lost maternal heterosis in herd
Problem in managing replacement females through the production system
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8. best Y x L crossbred sows
Roto-terminal
Mating System
Grandparent
best Y x L crossbred sows
mated to GGP Y or L semen X
Parent
Duroc x LW/LR cross
Market Hogs
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9. Relative Genetic Cost of Production ??
Cash or out of pocket costs
purchase breeding stock or semen or supplies
produce breeding stock
Salvage value of culled breeding stock
Interest rate on capital spent on purchases
Royalties or selection fees
In-herd multiplication costs
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10. In-Herd Multiplication Costs
A parent female with 100% heterosis is replaced with a maternal line female mated to a maternal line boar
potentially less maternal heterosis (< P/S/Y)
maternal offspring grow slower, have a lower lean percentage and poorer feed conversion
These are not out of pocket costs, but are hidden costs that must be accounted for
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11. Iowa Pork Industry Center
GENCOST
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12. Genetic COP with Alternative Replacement Female Systems
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13. Iowa Pork Industry Center
Can the Pig Farm Maintain the Same Level of Genetic Improvement While Making Their Own Females ??
Purchase terminal semen and GGP semen from seedstock supplier
Utilize the most effective technology currently being used by your seedstock supplier (Computerized BLUP technology)
Is your current multiplier doing more?
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14. Genetic Technologies Used by Genetic Suppliers
Quantitative Genetics
BLUP based BV estimation systems
phenotypic selection on structural and reproductive soundness
Molecular Genetics
Marker assisted selection
Transgenics
Which can be used at the farm??
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15. Requirements to Do BLUP Indexing
PigWin or PigChamp or equivalent data management system
Computer with math co-processor (486DX or higher CPU)
Pedigree information entered on the sows (her sire and dam) preferable
BLUP system that can be made extremely user friendly to use at the farm
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16. Iowa Pork Industry Center
BLUP Sow Indexing
Estimate the breeding value of animals for litter size, litter weight and wean to estrous interval
Create an SPI from the BV estimates for use in selection
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17. Demonstrate On-Farm BLUP System
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18. Iowa Pork Industry Center
BLUP Sow Indexing
Purebred GGP system:
At weaning, decide which GGP and GP sows to breed pure and which to breed cross and which to cull
Rototerminal system
At weaning, identify the top 15% of sows to breed maternally to make replacement females
Breed the rest terminally or cull
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19. Genetic Progress Example
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20. Genetic Progress Example
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21. Iowa Pork Industry Center
BLUP Sow Indexing
Primary reproductive traits are farrowing rate, number born alive, litter weaning weight and wean to estrous interval
Farrowing rate is confounded with boar fertility and not clean to measure
Other traits are lowly heritable
Therefore, BLUP genetic evaluation system is needed to make genetic progress
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22. Managing Replacement Gilts in Your Production System
1. Must identify potential replacement females at birth (date of birth, genetics, sire and dam)
2. Must keep track of potential replacement females through your production system
3. Should pen these gilts separately
4. Must develop them for maximum reproduction
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23. Frequency of Maternal Matings
Make replacement gilts weekly or monthly?
12% of one weeks matings or 50% of a months matings
Weekly matings
steady flow of gilts, greatest selection pressure, harder to manage small group of gilts
Monthly matings
larger group of gilts to manage, less selection pressure, monthly groups
What’s best for your farm?
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24. Management of Gilts for Maximum Reproduction
Maximum growth, maximum leanness, ???
NPB Maternal Line Genetic Evaluation Program trials examined four different nutritional programs and effects on future reproduction
High protein-High energy diets did not result in best reproduction
Better to develop the gilts below their growth potential for best reproduction
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25. Iowa Pork Industry Center
Summary
Closed herd management systems offer the potential for an improved health status
Internal multiplication of females offers the potential for cost savings
Internal multiplication of females requires more management by the farm
A genetic supplier with high quality genetics and health and AI is still required
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26. Iowa Pork Industry Center
Summary
Health concerns have forced some farms to move to a closed herd management system
Economic concerns force them to try to capture all the genetic improvement possible
It is possible for the better managed farms to use BLUP technology plus phenotypic selection
Improvement from molecular technology still must come from genetic supplier
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27. Iowa Pork Industry Center